Histoenzymological features of epithelial cells in lesions of oral mucosa in cysts and ameloblastomas of jaws

A histoenzymological study was carried out on 41 tissue specimens removed at biopsy and for surgical operations of the following lesions: benign hyperkeratosis, lichen planus, severe epithelial dysplasia, carcinoma in situ, epidermoid carcinoma, radicular cyst, odontogenic keratocyst and ameloblastoma. The purpose of this study was to study some possibly significant variations in levels of activities of oxidative enzymes, diaphorases, acid phosphatases and Naphthol esterases in such lesions (normal oral mucosa and epidermis serving as controls). In the lesions of the oral mucosa, these histoenzymological variations were not sufficiently characteristic to contribute to histological diagnosis, (i) In lichen planus, some vacuolated or necrotic basal cells lacked enzyme activities, whereas in the upper layers, enzyme activities were irregularly present, (ii) Benign hyperkeratosis showed enzymatic activities similar to those of the normal epidermis, namely high oxidative activities particularly prominent in basal cells and in granular layer, and esterase activity beneath the keratinized layer, (iii) In severe epithelial dysplasia, carcinoma in situ and epidermoid carcinoma, numerous variations of activities of oxidative enzymes, esterases and acid phosphatase were seen from one cell to the other. In cystic diseases of jaws, enzymatic activities were equally nonspecific in the epithelial lining of the radicular cyst and the odontogenic keratocyst (activities similar to those of normal oral epithelium and epidermis, respectively). But in common ameloblastoma, there was diffuse uniformly low oxidative enzymatic activities in the epithelium and high widespread activity of alkaline phosphatase in the stroma. The latter may be useful in differentiating the cystic acanthomatous variety of ameloblastoma from odontogenic keratocysts of the jaws.